The elderly are at high risk of falling, which is one of the most widespread causes of illness and even death. Mark, H. B. in Falls. The Merck Manual of Geriatrics, third Ed. 2000, pages 195-203, reports that at least 30% of people over 65 not living in hospitals experience falls at least once a year. Balance control is essential for performing everyday voluntary movements. Increasing age involves a higher risk of falling, due to bad posture.
Unstable balance related to age is negatively affected by possible pathological conditions and by unfavourably environmental and pharmacological conditions: in some cases even stability perception is impaired. Aizen, E., in Cautious Gait and Fear of Falling in the Elderly Harefuah November 2001, 140 (11): 1091 4-1115, reports that falling often involves a reduction in mobility, due to the fear of falling again. It is therefore apparent that limiting the possibility of falls would result in a great improvement of life conditions and possibly even in a longer life.
From the above it is apparent that improvement in posture control would result in a reduction of falls in elderly people. Posture control concerns all the static-dynamic processes affecting the position of a body in space and the parts of said body in reciprocal motion, maintaining the specific orientation with respect to the force of gravity. The function of the central nervous system is to transform an irregular flow of impulses into a regular activation, which is governed by suitable neuromotor nuclei.
The nervous signals that originate during motion were defined as a whole as proprioceptive sensitivity by Charles Sherrington in 1906. According to this definition, suitable stimuli are applied by the body to specific receptors, which are located within movement organs. Proprioceptive sensitivity refers to different kinds of stimuli: contact, pressure, pain. All the information collected through proprioceptors is an essential element for programming and controlling stillness and movement.
The most important proprioceptors are neuromuscular spindles and Golgi tendon organs, which are stretch receptors. Spindles are a highly specialised structure, widely distributed in the muscle parenchyma of skeletal muscles. Such a structure consists of a bundle of muscle fibres, enclosed in a capsule. Any muscle stretching is perceived by intrafusal fibres. Neuromuscular spindles are type 1 receptors, responding to energy changes with an electrical potential called “generating potential”. Spindle sensitivity to stretching is very high and is extremely important in the perception of one's position and orientation. A suitable action on proprioceptors is very important to achieve good posture control.
In recent years, great efforts have been made to find the best action on proprioceptors. Kramer, A., in Demography and Health Status; Geriatric Medicine, Second Ed. 1996; 18-27 and Herbert, D. R. et al.; Effective Physiotherapy BMJ, vol. 323, pages 788-790, showed that through proprioceptive stimulation involving muscle exercises for the legs, improvement of motor performance can be achieved. However, Studenski, S., in Guest Edition Clinics in Geriatric Medicine, November 1996, Gait and Balance Disorders, 635-658, pointed out that there is no correlation between muscle strengthening and balance. In any case, muscle training is presently the most common treatment for improving balance.